I saw Nate’s “Redboy’s” 46 monoblocks. I wish that I would have purchased them when he sold them.
Digressing, wonder if anyone has tried Schade feedback with these, perhaps 400v on the anode is possible with 250v on G2, but maybe the kink will be an issue.
I’m looking for 2w 7k output transformers. 5 watts maximum. Ideally down 3dB at 20Hz or below. The Hashimoto, Tamura, and Tango usually start to roll off around 45Hz. I’m here looking to see if any transformers can do better. When Mike was around he would wind small MagneQuest parallel feed output transformers that could be flat, and give you solid bass, down to 20’s Hz. Trying to see if there are any other alternatives or options out there and I appreciate all the responses. Thanks
Back in the 90s, an audio DIYer acquaintance breadboarded a 45 amp, which could be quickly switched between MagneQuest cobalt para-feed iron and Tango XE20S driving Western Electric 755As in Stereo Sound/SFB3-style open baffles. To my ears, the MQ PF iron sounded dark and mechanical. Bass response was pretty much similar but the XE20S produced a more organic midrange + richer top end overtones.
Fast forward to 2010 - I was commissioned to build an SE10 amp and used Hashimoto H20-14 OPTs for that project. It was only after we became good friends that I discovered that my SE10 amps replaced Wavelength 45 amps using MQ PF cobalt iron. Last year, I visited him and he's still using the same SE10 amps but has upgraded his speakers to G.I.P Laboratory Monitor 1s.
For the record, I was a fan of Mike's TFA204. I also owned a pair of his ES-025s, which used higher grade M4 laminations, but I enjoyed the TFA204s more. When my wife and I moved to the Philly area, I asked Mike if he'd wind me another pair, but alas, he didn't tell me he had a serious condition. 🙁
Having been in this hobby for decades, I've listened to many output transformers - Audio Note UK, Hammond, Hashimoto, MQ, Noguchi (now General Trans), Tamura, Tango, etc. IMO, part of the DHT-SE sonic allure is in the unbalanced DC running through the primary of an air-gapped output transformer. A huge chunk of iron with lots of inductance may give good bass response but the designer has to make sure that the top end harmonic integrity doesn't suffer as stated on page 3 of this 1934 RCA technical bulletin. Hence, a well designed output transformer is based on a good set of compromises!
Happy hunting and listening!
@je245 this is great information and the kind of feedback that I was hoping to get.
I have also heard that although 7k is the textbook loading for a 46 strapped for triode operation, that many prefer the sound of it loaded with 5k primary OPT.
I agree with you that bass response isn’t the only thing and that rich harmonics and spatiality maybe even more important to the organic sound.
I have heard good and not so good things about Amorphous, Cobalt, Nickel, Permalloy, and even Finemet core transformers as well with some preferring HiB.
On paper the Tamura F-7004 OPT checks all the boxes but not many reports on how it actually sounds in the circuit with 46 triode output.
At the other end of the cost spectrum, I have a 46 with the Sony/Tamradio Nickel, repurposed from Reel-to-Reel units, 2-watt transformers that sound wonderful to me.
In the end there may not be a way to predict the sound of the transformer as you said many variables and elements at play and the circuit design may be the dominant factor.
Thanks for your feedback.
I have also heard that although 7k is the textbook loading for a 46 strapped for triode operation, that many prefer the sound of it loaded with 5k primary OPT.
I agree with you that bass response isn’t the only thing and that rich harmonics and spatiality maybe even more important to the organic sound.
I have heard good and not so good things about Amorphous, Cobalt, Nickel, Permalloy, and even Finemet core transformers as well with some preferring HiB.
On paper the Tamura F-7004 OPT checks all the boxes but not many reports on how it actually sounds in the circuit with 46 triode output.
At the other end of the cost spectrum, I have a 46 with the Sony/Tamradio Nickel, repurposed from Reel-to-Reel units, 2-watt transformers that sound wonderful to me.
In the end there may not be a way to predict the sound of the transformer as you said many variables and elements at play and the circuit design may be the dominant factor.
Thanks for your feedback.
If you're only looking at one watt output, then most good quality SE OPTs should manage the low frequency response without issue.
My smaller 45 SE monoblocks use the Hashimoto H507S OPTs with the 5K load and 34 ma of current. At 1-watt output, the frequency response is within 1dB from 25Hz to 50KHz. Also note that I purposely roll them off a bit on the low end.
Regards, KM
My smaller 45 SE monoblocks use the Hashimoto H507S OPTs with the 5K load and 34 ma of current. At 1-watt output, the frequency response is within 1dB from 25Hz to 50KHz. Also note that I purposely roll them off a bit on the low end.
Regards, KM
They make custom transformers as well, so ask them for a quote.
The 46 dual grid output tube is very rugged! In spite of the fact that the triode'd 46 on a 5K load + 45 operating points looked prettier on the scope and produced better numbers, I liked the sound better using the specs in the tube manual.
That's because none of them are perfect.
That said, I was never impressed by the Tamura F5000 amorphous series, too detailed and analytical for my taste. I prefer the nickel F7000 series as well as the Tango Hirata era NY15s and 10429 permalloys!
I like Finemet because it retains much of the organic quality I hear from permalloy. However, when I inserted a Finemet FM-ATVR1 AVC in my system wherein my conical SPU went through the FM MCT-1 step up > 5693 phono > triod'ed 6F6 + Hashimoto HL6-20K > AVC > SE2A3 with Slagle nickel plate chokes on triode'd 6C6s with Tamura F7002 permalloys > Altec 753Cs - the sound veered towards clinical. I very much preferred the tonal balance with the Intact Audio nickels in the AVC position. When I substituted an amp equipped with an EI or regular C-core SE OPT, the sound was still better balanced with the nickel AVC. Lesson learned - too much exotic alloys can = disappointment.
Hashimoto shuns the use of exotic alloys in their transformers. I built a hifi system for a cousin during lockdown and used Hashimoto iron exclusively. When he saw the FM-MCT1 in my blog, he asked if that would be an upgrade to his HM7s. So I inquired if there was something he found lacking in his system. When he replied no, I advised that he should keep the HM7s and buy more LPs!
IME/IMHO, the improvement (for lack of a better word) brought forth by permalloy and Finemet is manifested mostly in the midrange not in the frequency extremes.
My SE10 amp uses an F7004 (I mismatch the secondary to reflect a 14k pri. Z), which I use in my mono hifi set up. I also have a SE46 mono amp using a UTC S14. If you can find a good used pair of F7004s, that should work well with a triode'd 46 and give more bottom heft than the S14 or smaller 7K OPTs. As good as the F7004 looks on paper, its bandwidth isn't as wide as the F7002. Back in the 90s knowledgeable people in the Sound Practices-list were discussing that as the primary Z gets higher, the harder it is to maintain frequency extension at the extremes.
It may have been already suggested earlier, you ought to check out a G-Trans Finemet 7k in the 10-14W range. I've been very happy with my FM6WS.
I love that bonsai OPT! I use it in my Simple triode'd 6F6/6V6 amp as well as in a line stage preamp driven by a 12B4A.
The driver stage definitely has a significant influence in the sound of an amp.
Through the years, I've learned to use test equipment only as a guide because I've had circuits, transformers, components, etc. which measured and looked great but sounded bad and vice versa. Finding something which measured well and sounded good wasn't as consistent as I'd expected. I also realized that everyone reacts to music in so many different ways.
Words are also limited in terms of describing music and sound. In the 80s, I was a Stereophile and TAS subscriber. Upon discovering The Audio Amateur, I was able to fix/hack Dynakit preamps/amps and compare them to my store bought conrad johnson, Berning, NAD, Hafler, etc. Then I was introduced to Joe Roberts and his Sound Practices magazine in the early 90s enabling me to build and tinker with a hifi set up that makes me enjoy music even more!
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@carlos269 - the H507S suggested by @kmaier in post #27 is also well worth considering. I use the 3.5K H203S in my SE2A3 mono amp.
Note that the graphs and specifications for the 7-watt Hashimoto OPTs are at their rated output of 7 watts and their rated primary DC current.
Running them at lower current and power accounts for the difference in frequency response. This is typical for most good quality OPTs. Even the original Dynaco P-P OPTs had two frequency response ratings at two power levels, 3 dB apart.
I also use the H203S for my 2A3 version of the 45 Monoblock referenced previously. Really great iron in general. I can say the same for their filter chokes and power transformers. For all of my current and future gear, all iron is Hashimoto.
Regards, KM
Running them at lower current and power accounts for the difference in frequency response. This is typical for most good quality OPTs. Even the original Dynaco P-P OPTs had two frequency response ratings at two power levels, 3 dB apart.
I also use the H203S for my 2A3 version of the 45 Monoblock referenced previously. Really great iron in general. I can say the same for their filter chokes and power transformers. For all of my current and future gear, all iron is Hashimoto.
Regards, KM
I've been looking at the 46 datasheet. The referenced specification for 1.25W output is listed there with Grid 2 ties to the plate. As the Hashimoto SE OPTs also feature screen taps, you could also try running the 46 in single-ended ultralinear configuration. Chances are you could get a bit more power from the 46 and still maintain a low distortion figure. Something to think about.
Regards, KM
Regards, KM
Best in audio is a subjective thing, however if I had such a project in America, I would get in touch with Dave Slagle :
https://intactaudio.com/tran.html
regards,
dennis h
https://intactaudio.com/tran.html
regards,
dennis h
There's an alternative argument that smaller OPTs sound better. We've already mentioned the Sony Tamradio ones for instance, which I have.
For the most part, have been building PP. The bigger they get, the more likely the parasitics are going to get larger. More capacitance and leakage L are not good for high frequency performance. With active cross overs at line level, it is possible to get adequate power without requiring it all to go through one OPT.
Sooo...with open loop amps, build the LF amplifier with what would be ugly OPT's if required to work at 5kHz...and make the same sort of shift for the upper frequency amps; if they're not going to see 60 cps signal, they can be wound for better upper frequency performance.
Douglas
Sooo...with open loop amps, build the LF amplifier with what would be ugly OPT's if required to work at 5kHz...and make the same sort of shift for the upper frequency amps; if they're not going to see 60 cps signal, they can be wound for better upper frequency performance.
Douglas
Small SE opts create high 2nd and 3rd harmonic distortion at low frequencies and this makes the sound "strong" and "rich".
With some of the smaller transformers saturation can have a euphoric sound rich in harmonics and bass compression, which will sound warm and organic. But it is also my understanding that lower power smaller transformers yield more extended bandwidth and are less compromised as pointed in the post above with parasitic capacitance effects. The inductance of larger oversized transformers may also be an issue. I have a pair of 5k SA-11 Amorphous core Monolith Magnetics OPT that I could try, but I think that I will get better results with the small Sony/Tamradio nickel OPT’s.
I have also seen transformers that measure well that do not sound as good. Others report that when using output transformers with dual 5k and 7k primaries like the Electra-Print PSSS OPT’s with the 46 strapped in triode that they prefer the warmer and more organic sound using the 5K primary than the leaner more analytical sound when using the 7K primary.
Based on what I have read, nickel core or laminates do offers special sound, but similar sound can also be achieved with other core materials. The General Transformers Finemet OPT are also an option. I leaning on also trying the boutique Muse Coils HiB OPT’s from Alexander.
Because of this thread now I have more choices to consider.
I have also seen transformers that measure well that do not sound as good. Others report that when using output transformers with dual 5k and 7k primaries like the Electra-Print PSSS OPT’s with the 46 strapped in triode that they prefer the warmer and more organic sound using the 5K primary than the leaner more analytical sound when using the 7K primary.
Based on what I have read, nickel core or laminates do offers special sound, but similar sound can also be achieved with other core materials. The General Transformers Finemet OPT are also an option. I leaning on also trying the boutique Muse Coils HiB OPT’s from Alexander.
Because of this thread now I have more choices to consider.